271,281 research outputs found
Quantitative Ultrasound of Cortical Bone in the Femoral Neck Predicts Femur Strength: Results of a Pilot Study
No full textArticle first published online: 15 JAN 2013 Pour consulter la version éditeur DOI: 10.1002/jbmr.1742A significant risk of femoral neck (FN) fracture exists for men and women with an areal bone mineral density (aBMD) higher than the osteoporotic range, as measured with dual-energy X-ray absorptiometry (DXA). Separately measuring the cortical and trabecular FN compartments and combining the results would likely be a critical aspect of enhancing the diagnostic capabilities of a new technique. Because the cortical shell determines a large part of FN strength a novel quantitative ultrasound (QUS) technique that probes the FN cortical compartment was implemented, aimed at testing the sensitivity of the method to variations of FN cortical properties and FN strength. Nine femurs (women, mean age 83 years) were subjected to QUS to measure the through transmission time-of-flight (TOF) at the FN and mechanical tests to assess strength. Quantitative computed tomography (QCT) scans were performed to enable analysis of the dependence of TOF on bone parameters. DXA was also performed for reference. An ultrasound wave propagating circumferentially in the cortical shell, which TOF was not influenced by the properties of the trabecular compartment Q3, was measured in all specimens. Averaged TOF for nine FN measurement positions/orientations was significantly correlated to strength (R² = 0.79) and FN cortical QCT variables: total BMD (R² = 0.54); regional BMD in the inferoanterior (R² = 0.90) and superoanterior (R² = 0.57) quadrants; and moment of inertia (R² = 0.71). The results of this study demonstrate that QUS can perform a targeted measurement of the FN cortical compartment. Because the method involves mechanical guided waves, the QUS variable is related to the geometric and material properties of the cortical shell (cortical thickness, tissue elasticity, and porosity). This work opens the way to a multimodal QUS assessment of the proximal femur, combining our approach targeting the cortical shell with the existing modality sensitive to the trabecular compartment. In vivo feasibility of our approach has to be confirmed with experimental data in patients
The Warwick Hip Trauma Evaluation – an abridged protocol for the WHiTE Study : a multiple embedded randomised controlled trial cohort study
No full textFractures of the proximal femur are one of the greatest challenges facing the medical community, constituting a heavy socioeconomic burden worldwide. The National Hip Fracture Audit currently provides a framework for service evaluation. This evaluation is based upon the assessment of process rather than assessment of patient-centred outcome and therefore it fails to provide meaningful data regarding the clinical effectiveness of treatments. This study aims to capture data from the cohort of patients who present with a fracture of the proximal femur at a single United Kingdom Major Trauma Centre. Patient-centred outcomes will be recorded and provide a baseline cohort within which to test the clinical effectiveness of experimental interventions
Protocol for the United Kingdom Rotator Cuff Study (UKUFF) : a randomised controlled trial of open and arthroscopic rotator cuff repair
No full textThis project was funded by the NIHR Health Technology Assessment programme (project number 05/47/02). J. L. Rees has received a grant from Oxford University which is related to this paper. J. Dawson reports that Oxford University has received a grant from HTA which is related to this paper, as well as a study grant.Peer reviewe
Adjusting bone mass for differences in projected bone area and other confounding variables: an allometric perspective.
No full textThe traditional method of assessing bone mineral density (BMD; given by bone mineral content [BMC] divided by projected bone area [Ap], BMD = BMC/Ap) has come under strong criticism by various authors. Their criticism being that the projected bone "area" (Ap) will systematically underestimate the skeletal bone "volume" of taller subjects. To reduce the confounding effects of bone size, an alternative ratio has been proposed called bone mineral apparent density [BMAD = BMC/(Ap)3/2]. However, bone size is not the only confounding variable associated with BMC. Others include age, sex, body size, and maturation. To assess the dimensional relationship between BMC and projected bone area, independent of other confounding variables, we proposed and fitted a proportional allometric model to the BMC data of the L2-L4 vertebrae from a previously published study. The projected bone area exponents were greater than unity for both boys (1.43) and girls (1.02), but only the boy's fitted exponent was not different from that predicted by geometric similarity (1.5). Based on these exponents, it is not clear whether bone mass acquisition increases in proportion to the projected bone area (Ap) or an estimate of projected bone volume (Ap)3/2. However, by adopting the proposed methods, the analysis will automatically adjust BMC for differences in projected bone size and other confounding variables for the particular population being studied. Hence, the necessity to speculate as to the theoretical value of the exponent of Ap, although interesting, becomes redundant
Upper Limb Muscle–Bone Asymmetries and Bone Adaptation in Elite Youth Tennis Players
No full textIntroduction: The study of tennis players allows the nonracket arm to act as an internal control for the exercising racket arm. In
addition, the study of the upper limbs removes the influence of gravitational loading, allowing the examination of the influence of
muscular force on bone adaptation. Methods: The role of muscular action on bone, strength parameters of the radius, ulna (both at
4% and 60% distal–proximal ulnar length), and humerus (at 35% distal–proximal humerus length) as well as muscle size in both arms of
50 elite junior tennis players (mean T SD age = 13.5 T 1.9 yr) were measured with peripheral quantitative computed tomography (pQCT).
Results: Strong relationships were found between muscle size and bone size in both arms (all correlations, P G 0.001, R2 = 0.73–0.86).
However, the muscle–bone ratio was significantly lower (P G 0.001) in the upper arm on the racket side (compared with the contralateral
arm). In addition, material eccentricity analysis revealed that bone strength in bending and torsion increased more than strength in
compression as the moment arms for these actions (bone length and width, respectively) increased (in all cases, P 9 0.001, R2 = 0.06–0.7)
with relationships being stronger in torsion than in bending. Large side differences were found in bone strength parameters and muscle
size in all investigated sites, with differences in distal radius total BMC (+37% T 21%) and humerus cortical cross-sectional area (+40% T
12%) being most pronounced (both P G 0.001). Conclusions: These results support a strong influence of muscular action on bone
adaptation; however, interarm muscle–bone asymmetries suggest factors other than local muscle size that determine bone strength. The
results also suggest that torsional loads provide the greatest stress experienced by the bone during a tennis stroke
Scintigraphic assessment of bone status at one year following hip resurfacing : comparison of two surgical approaches using SPECT-CT scan
No full textObjectives: To study the vascularity and bone metabolism of the femoral head/neck following hip resurfacing arthroplasty, and to use these results to compare the posterior and the trochanteric-flip approaches.
Methods: In our previous work, we reported changes to intra-operative blood flow during hip resurfacing arthroplasty comparing two surgical approaches. In this study, we report the vascularity and the metabolic bone function in the proximal femur in these same patients at one year after the surgery. Vascularity and bone function was assessed using scintigraphic techniques. Of the 13 patients who agreed to take part, eight had their arthroplasty through a posterior approach and five through a trochanteric-flip approach.
Results: One year after surgery, we found no difference in the vascularity (vascular phase) and metabolic bone function (delayed phase) at the junction of the femoral head/neck between the two groups of patients. Higher radiopharmaceutical uptake was found in the region of the greater trochanter in the trochanteric-flip group, related to the healing osteotomy.
Conclusions: Our findings using scintigraphic techniques suggest that the greater intra-operative reduction in blood flow to the junction of the femoral head/neck, which is seen with the posterior approach compared with trochanteric flip, does not result in any difference in vascularity or metabolic bone function one year after surgery
EXOGEN ultrasound bone healing system for long bone fractures with non-union or delayed healing: a NICE medical technology guidance
No full textOpen Access. This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and the source are credited.This article has been made available through the Brunel Open Access Publishing Fund.A routine part of the process for developing National Institute for Health and Care Excellence (NICE) medical technologies guidance is a submission of clinical and economic evidence by the technology manufacturer. The Birmingham and Brunel Consortium External Assessment Centre (EAC; a consortium of the University of Birmingham and Brunel University) independently appraised the submission on the EXOGEN bone healing system for long bone fractures with non-union or delayed healing. This article is an overview of the original evidence submitted, the EAC’s findings, and the final NICE guidance issued.The Birmingham and Brunel Consortium is funded by NICE to act as an External Assessment Centre for the Medical Technologies Evaluation Programme
Bone fractures after menopause
No full textEvery year 30% of individuals above age 65 fall, and falls are the principal cause of bone fractures. To reduce fracture incidence requires both prevention of falls and maintenance of bone strength.PubMed searches were performed, for studies of the epidemiology of fractures, bone physiology, endocrine effects, osteoporosis measurement, genetics, prevention and effectiveness. Topic summaries were presented to the Workshop Group and omissions or disagreements were resolved by discussion.Ageing reduces bone strength in post-menopausal women because estrogen deficiency causes accelerated bone resorption. Bone mineral density (BMD) decreased more than 2.5 standard deviation below the mean of healthy young adults defines osteoporosis, a condition associated with an increased risk of fractures. Risk factors such as age and previous fracture are combined with BMD for a more accurate prediction of fracture risk. The most widely used assessment tool is FRAX (TM) which combines clinical risk factors and femoral neck BMD. General preventive measures include physical exercise to reduce the risk of falling and vitamin D to facilitate calcium absorption. Pharmacological interventions consist mainly in the administration of inhibitors of bone resorption. Randomized controlled trials show treatment improves BMD, and may reduce the relative fracture risk by about 50% for vertebral, 20-25% for non-vertebral and up to 40% for hip fractures although the absolute risk reductions are much lower.Although diagnosis of osteoporosis is an important step, the threshold for treatment to prevent fractures depends on additional clinical risk factors. None of the presently available treatment options provide complete fracture prevention.</p
Peak bone mass after exposure to antenatal betamethasone and prematurity: Follow-up of a randomized controlled trial
No full textSmall birth size is associated with reduced adult bone mass. We determined if antenatal betamethasone exposure, birth weight, or prematurity affects peak bone mass in 174 adults. Antenatal betamethasone exposure did not. Lower birth weight and prematurity predicted reduced adult height. Slower fetal growth rather than prematurity predicted lower bone mass, but this lower bone mass was appropriate for reduced adult height
Correlations between cancellous bone architecture and its dynamic behaviour
No full textPrevious studies showed that in vivo evaluation of the fracture risk of cancellous bone can be assessed by identifying the relationships between its microarchitecture description extracted from clinical imaging and its mechanical properties. The mechanical properties under dynamic loadings (with and without confinement) were obtained and compared to quasi-static ones. The architectural parameters of each specimen were extracted from pQCT images and split into four groups: geometry, topology, connectivity and anisotropy. Results show that architectural parameters are strong determinants of mechanical behaviour for the different applied boundary conditions.http://icills2014.org/wp-content/uploads/2014/01/Marrianne-Prot.pd
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